No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Biomechanics of the Bankart Repair: The Relationship Between Glenohumeral Translation and Labral Fixation Site
Abstract
The specific aim of this study was to quantify glenohumeral translations in cadaveric shoulders after repair of the superior and middle regions of a surgically created Bankart lesion and after repair of the superior, middle, and inferior regions of the same lesion. Anterior-posterior, superior-inferior, and medial-lateral translations in nine cadaveric specimens were tested with shoulders in 0 degree, 45 degrees, and 90 degrees of humeral abduction and varying degrees of humeral rotation. There was statistically significantly less anterior and inferior translation after three-site labral repair compared with after two-site labral repair, and this effect was greatest at 90 degrees of glenohumeral abduction. The decreased translations demonstrated with three-site repair emphasized the importance of careful repair of the labrum to the inferior glenoid rim during a Bankart reconstruction and suggested that failure to do so may be a contributing factor to recurrent instability after anterior shoulder reconstruction.
... There is also no current consensus on the position of the suture anchor relative to the glenoid clock face. Anchor positioning in various combinations (usually three anchors) have been described in the literature extending from 1.30 around to 5.30 [2,[10][11][12][13][14][15]. Although there has been no study to determine the best clock face position for suture anchors, surgeons should be aware about the theoretical effect of the chosen position on the strength of the Bankart repair. ...
... The cortical layer thickness and the bone density of the glenoid decrease from superior to inferior part of the glenoid, and hence, the pullout strength of the anchors is higher in the superior portion of the glenoid [16] and likelihood of failure (FOS) was shown to be lower in ROI-1. Although the size of the anterior labral tear will usually determine the number and the location of the suture anchors inserted in the glenoid, it is crucial that the torn capsulo-labral tissue is securely repaired to the inferior glenoid rim to ensure a successful Bankart reconstruction [11]. ...
As the use of glenoid suture anchors in arthroscopic and open reconstruction, for instability after Bankart lesions of the shoulder, increases, an emerging problem has been the incidence of glenoid rim fractures through suture drill holes. Very little is known regarding the effect of the Hill-Sachs lesion on the glenoid's susceptibility to fracture and how drill hole location can further affect this. This study used finite element modelling techniques to investigate the risk of fracture of the glenoid rim in relation to variable sized Hill-Sachs defects impacting on the anterior glenoid edge with suture anchor holes placed in varying positions. The distribution of Von Mises (VM) stresses and the Factor of Safety (FOS) for each of the configurations were calculated. The greatest peak in von Mises (VM) stresses was generated when the glenoid was loaded with a small Hill-Sachs lesion. The VM stresses were lessened and the FOS increased (reducing likelihood of failure) with increasing size of the Hill-Sachs lesion. Placement of the suture drill holes at 2mm from the glenoid rim showed the highest risk of failure; and when combined with a medium sized Hill-Sachs lesion, which matched the central line of the drill holes, a potentially clinically significant configuration was presented. The results of this study are useful in assisting the surgeon in understanding the interaction between the Hill-Sachs lesion size and the placement of suture anchors with the purpose of minimising the risk of subsequent rim fracture with new injury.
... Although numerous clinical studies have examined the relevant biomechanical forces pertaining to rotator cuff repair performed with suture anchors, [4][5][6] there is less biomechanical data in the literature that reflects an accurate recreation of the forces placed across a labral repair or capsulolabral reconstruction with suture anchors. [7][8][9][10][11] ...
... Repair constructs with multiple points of fixation have been shown in the literature as an important determinant of capsulolabral reconstruction success. 9 We believe a 3.5-mm to 4.1-mm diameter is the maximum size for an optimal suture anchor to be used for labral repair and capsulolabral reconstruction. Ideally, the smallest implant of sufficient strength to obtain the most stable fixation for soft-tissue healing will allow not only multiple fixation points but also minimize articular surface compromise and maximize restoration of the normal anatomy. ...
Treatment of glenohumeral instability and capsulolabral pathology continues to evolve as arthroscopic techniques improve. A growing body of biomechanical and clinical research provides an enhanced perspective on results obtained with both arthroscopic and open treatment of these conditions. Labral repair and capsulolabral reconstruction can effectively be treated with suture anchors by both arthroscopic and open methods. Suture anchors are low-profile fixation devices that can minimize articular surface compromise and afford an anatomic reconstruction of the labrum and glenohumeral ligament complex. Although the use of suture anchors has become increasingly common to obtain stable fixation and healing at the bone-tendon interface in rotator cuff repair, critical distinctions exist between this function and their implementation in labral repair and capsulolabral reconstruction. This article examines the technical aspects of labral repair and capsulolabral reconstruction with metallic and bioabsorbable suture anchors. The emphasis is on implant options, technical advantages, potential limitations, and relevant biomechanical considerations to better achieve an optimal outcome.
... The repair of the inferior portion of the inferior glenohumeral ligament is critical to reduce anterior translation in a repaired Bankart lesion. 9 The middle glenohumeral ligament (MGHL) is also important in resisting anterior translation of the humeral head. Although the MGHL has its greatest contribution to stability in lesser degrees of abduction, it still shows significant strain in 90° of abduction. ...
... 4,22 Prior biomechanical investigation has shown that, to recreate normal translation, an anchor must be placed in the anteriorinferior 5-o'clock position. 9 Many studies have addressed how to maximize the strength of the Bankart repair. It is logical that the inclusion of additional, more robust tissue at this interface (the MGHL) may significantly strengthen surgical repairs. ...
Surgical treatment for traumatic shoulder instability has progressed in tandem with the evolution of the current understanding of the anatomy and biomechanics of the shoulder. Proponents of incorporating the middle glenohumeral ligament (MGHL) in Bankart repair believe this technique could increase repair strength. The purpose of this biomechanical study was to compare the range of motion and humeral head kinematic changes that result from including the MGHL in a Bankart repair in an effort to identify possible changes in shoulder biomechanics as a result of this addition in surgical repair.
Six cadaveric shoulders were tested in 4 conditions: intact, Bankart lesion, repair excluding the MGHL, and repair including the MGHL. Each condition was tested for range of motion, glenohumeral translation, and humeral head apex position. Standard Bankart repair and repair with MGHL inclusion resulted in decreased range of motion, but no statistically significant difference was found between the 2 repair types ( P =.846). Anterior translation was significantly reduced with both the Bankart repair (4.8±.9; P =.049) and included MGHL repair (4.6±0.9; P =.029). No statistically significant difference was found between both repairs ( P =.993). Although both repairs showed posterior displacement of the humeral head apex when in external rotation, this trend only reached statistical significance when compared with the Bankart lesion in 90° of external rotation ( P =.0456); however, no significant difference was found between the 2 repairs ( P =.999).
Inclusion or exclusion of the MGHL in a Bankart repair does not significantly affect the range of motion, translation, or kinematics of the glenohumeral joint.
... Some cadaveric studies have investigated the surgical effect on anterior translation of the humeral head. 1,3,14,22 Marquardt et al 14 reported that anterior translation was decreased at both 0 and 90 of glenohumeral abduction with external rotation after Bankart repair (by 2.7 mm at 0 and 2.9 mm at 90 ). Black et al 3 investigated the change in anterior translation after Bankart repair, at 0 , 45 , and 90 of glenohumeral abduction with neutral rotation, and reported that the surgical effect was greatest at 90 and smallest at 0 (0.9 mm at 0 , 2.9 mm at 45 , and 3.4 mm at 90 ); our findings were consistent with their results. ...
Background
The changes in glenohumeral joint stability after surgery in a clinical setting are yet unknown.
Purpose/Hypothesis
This study aimed to compare the anterior humeral head translation between pre- and postsurgical conditions using ultrasonography. It was hypothesized that ultrasonographic assessment would reveal decreased anterior translation.
Study Design
Case series; Level of evidence, 4.
Methods
A total of 27 patients (24 male, 3 female; mean age, 24.1 ± 9.7 years) with anterior shoulder instability were studied prospectively. All the patients underwent the arthroscopic Bankart-Bristow procedure under general anesthesia, and ultrasonographic evaluation was performed before and immediately after surgery. The forearm was fixed with an arm positioner in the beach-chair position, and the ultrasonographic transducer was located at the posterior part of the shoulder to visualize the humeral head and glenoid rim at the level of interval between the infraspinatus tendon and teres minor tendon. The upper arm was drawn anteriorly with a 40-N force at 0°, 45°, and 90° of shoulder abduction with neutral rotation. The distance from the posterior edge of the glenoid to that of the humeral head was measured using ultrasonography with and without anterior force. Anterior translation was defined by subtracting the distance with anterior force from the distance without anterior force.
Results
The humeral head position was translated posteriorly immediately after surgery in all patients. Anterior translation decreased significantly after surgery at 45° (7.7 ± 4.3 vs 5.8 ± 2.0 mm; P = .031) and 90° (8.9 ± 3.4 vs 6.1 ± 2.2 mm; P < .001) of abduction, whereas there was no difference between pre- and postsurgical translation at 0° of abduction (4.9 ± 2.3 vs 4.0 ± 2.1 mm, P = .089).
Conclusion
Ultrasonographic assessment immediately after a Bankart-Bristow procedure showed the humeral head was translated posteriorly relative to the glenoid at 0°, 45°, and 90° of abduction. The surgery also decreased anterior translation in response to an anteriorly directed force at 45° and 90° of abduction.
... Several studies [3][4][5][6][7][8][9][10][11] have reported a significant correlation between labral fixation and glenohumeral translation. In contrast, Kim et al. 12 reported an insignificant correlation between the extent of the labral lesion and the frequency of glenohumeral dislocation. ...
Background:
Tears of the glenoid labrum are common after dislocation of the glenohumeral joint. The outcome for healing or surgical reconstruction of the glenoid labrum relies on the extent of its vascularization. This study aims to evaluate the glenoid labrum blood supply and to determine its regional vascularity.
Materials and methods:
A total of 140 shoulders (30 male and 40 female cadavers) were examined: mean age 81.5 years, range 53-101 years. All blood vessels around the glenohumeral joint were dissected and recorded. Ten specimens with the glenoid labrum and fibrous capsule attached were randomly selected and detached at the glenoid neck and subjected to decalcification. Sections (10-20 μm) were cut through the whole thickness of each specimen from the centre of the glenoid fossa perpendicular to the glenoid labrum at 12 radii corresponding to a clock face superimposed on the glenoid. Sections were stained using haematoxylin and eosin and then examined.
Results:
The blood supply to the glenoid labrum is by direct branches from the second part of the axillary artery, subscapular, circumflex scapular and anterior circumflex humeral and posterior circumflex humeral arteries, as well as branches of muscular arteries supplying the surrounding muscles.
Conclusion:
This study shows that the glenoid labrum has a rich blood supply suggesting that, regardless of the types of the glenoid labrum lesions or their management, an excellent outcome for glenoid labrum healing and joint stability is possible. The observations also suggest that the blood supply to the glenoid labrum is sufficient, enabling its reattachment.
... Soft tissue fixation strength has been shown to be proportional to the number of suture anchors, which when focusing on arthroscopic capsular shift and glenoid labrum repair means stronger repairs require a greater number of fixation points. [1,2] For shoulder arthroscopy, the suture anchor has become the most commonly utilized method of glenoid labrum fixation. [3,4] While many factors play a role in the successful treatment of shoulder instability, Boileau et al. in a study focusing on anterior labrum repair, found "the number of sutures and anchors was significantly related to failed arthroscopic stabilization; specifically, patients who had three anchors or fewer had higher rates of recurrent instability (P = 0.03)." ...
The 2-year outcomes of patients undergoing repair of triple labrum tears using an all-suture anchor device were assessed.
Eighteen patients (17 male, one female; mean age 36.4 years, range: 14.2-62.3 years) with triple labrum tears underwent arthroscopic repair using the 1.4 mm JuggerKnot Soft Anchor (mean number of anchors 11.5, range: 9-19 anchors). Five patients had prior surgeries performed on their operative shoulder. Patients were followed for a mean of 2.0 years (range: 1.6-3.0 years). Constant-Murley shoulder score (CS) and Flexilevel scale of shoulder function (FLEX-SF) scores were measured, with preoperative and final postoperative mean scores compared with a paired Student's t-test (P < 0.05). Magnetic resonance imaging (MRI) was also performed at final postoperative.
Overall total CS and FLEX-SF scores increased from 52.9 ± 20.4 to 84.3 ± 10.7 (P < 0.0001) and from 29.3 ± 4.7 to 42.0 ± 7.3 (P < 0.0001), respectively. When divided into two groups by whether or not glenohumeral arthrosis was present at the time of surgery (n = 9 each group), significant improvements in CS and FLEX-SF were obtained for both groups (P < 0.0015). There were no intraoperative complications. All patients, including contact athletes, returned to their preinjury level of sports activity and were satisfied. MRI evaluation revealed no instances of subchondral cyst formation or tunnel expansion. Anchor tracts appeared to heal with fibrous tissue, complete bony healing, or combined fibro-osseous healing.
Our results are encouraging, demonstrating a consistent healing of the anchor tunnels through arthroscopic treatment of complex labrum lesions with a completely suture-based implant. It further demonstrates a meaningful improvement in patient outcomes, a predictable return to activity, and a high rate of patient satisfaction.
Level IV case series.
... The increases in glenohumeral translation and ROM seen with a large HAGL lesion observed in this study were greater than those found in previous biomechanical studies of Bankart lesions corresponding to similar clock face positions [3,7,20]. By removing the capsule from its attachment on the humerus relative to the clock face position, a much larger lesion is created as compared to the glenoid. ...
Background:
Humeral avulsion of the glenohumeral ligaments (HAGL) has become a recognized cause of recurrent shoulder instability; however, it is unknown whether small and large HAGL lesions have similarly destabilizing effects and if large lesion repair results in restoration of stability.
Questions/purposes:
In a cadaver model, we evaluated the effect of small and large HAGL lesions and large HAGL lesion repair on glenohumeral ROM, translation, and kinematics.
Methods:
We measured rotational ROM, humeral head translation under load, and humeral head apex position in eight cadaveric shoulders. Each specimen was tested in 60° glenohumeral abduction in the scapular and coronal planes under four conditions: intact, small HAGL lesion (mean ± SD length, 18 ± 1.8 mm), large HAGL lesion (36.8 ± 3.6 mm), and after large HAGL lesion repair. For each condition, we measured maximum internal and external rotation with 1.5 Nm of torque; glenohumeral translation in 90° external rotation with 15- and 20-N force applied in the anterior, posterior, superior, and inferior directions; and humeral head apex position throughout ROM. Repeated-measures ANOVA was used for statistical analysis.
Results:
Small HAGL lesions did not change ROM, translation, or kinematics from the normal shoulder; however, these parameters changed with large HAGL lesions. Maximum external rotation and total ROM increased in the scapular (13.8° ± 9.4°, p < 0.001; 19.0° ± 16.5°, p < 0.001) and coronal (21.4° ± 10.6°, p < 0.001; 29.1° ± 22.1°, p < 0.001) planes. With anterior force, anterior-inferior translation increased in both planes (mean increase for both loads and planes: anterior: 9.1 ± 9.5 mm, p < 0.01; inferior, 5.7 ± 6.6 mm, p < 0.03). In the coronal plane, posterior and inferior translation also increased (4.9 ± 5.4 mm, p < 0.01; 7.1 ± 9.9 mm, p < 0.03; averaged for both loads). The humeral head apex shifted 3.7 ± 4.9 mm anterior (p = 0.04) and 2.8 ± 2.6 mm lateral (p = 0.004) in the scapular plane and 3.7 ± 3.4 mm superior (p = 0.006) and 4.1 ± 2.6 mm lateral (p < 0.001) in the coronal plane. HAGL lesion repair decreased ROM and translation in both planes and restored humeral head position in maximum external rotation.
Conclusions:
Anterior large HAGL lesions increase ROM and glenohumeral translation. After large HAGL lesion repair, stability of the shoulder can be restored.
Clinical relevance:
Surgeons should be aware of the possibility of HAGL lesions in patients with shoulder instability, and if large HAGL lesions are diagnosed, surgeons should consider repairing the lesions.
... Most frequently, this produces an anteroinferior capsulolabral avulsion, classically referred to as a soft tissue Bankart lesion, which serves as a contributing factor to recurrent shoulder instability, often necessitating surgical stabilization. [1][2][3][4][5] Complex shoulder instability differs in that in addition to the soft tissue Bankart lesion, recurrent instability is attributable to associated osseous lesions of the glenoid, humeral head, or both. 1,[6][7][8][9] This article reviews the effect of these lesions and their associated treatment options. ...
Surgical management of recurrent shoulder instability can be complicated in the setting of associated osseous defects of the glenoid, humeral head, or both. A wide variety of surgical options exist for the management of complex shoulder instability. Interventions for addressing glenoid and humeral head bone defects, and their biomechanical effects, are reviewed. Further studies are required to delineate critical defect values and develop validated treatment algorithms.
... A linear force was applied to the humeral head, and translation on the glenoid was measured. Such studies found the inferior glenohumeral ligament to be the primary static restraint to anterior glenohumeral instability [9,11,12], and after the ligament was repaired, normal translation of the joint was restored [13]. A critical size of the glenoid rim defect that may occur after dislocation in vivo was also found [14] . ...
A novel cadaveric model for anterior-inferior shoulder dislocation using forcible apprehension positioning is presented. This model simulates an in vivo mechanism and yields capsulolabral lesions. The scapulae of 14 cadaveric entire upper limbs (82 +/- 9 years, mean +/- standard deviation) were each rigidly fixed to a custom shoulder-testing device. A pneumatic system was used with pulleys and cables to simulate the rotator cuff and the deltoid muscles (anterior and middle portions). The glenohumeral joint was then positioned in the apprehension position of abduction, external rotation, and horizontal abduction. A 6-degree-of-freedom load cell (Assurance Technologies, Garner, North Carolina) measured the joint reaction force that was then resolved into three orthogonal components of compression force, anteriorly directed force, and superiorly directed force. With the use of a thrust bearing, the humerus was moved along a rail with a servomotor-controlled system at 50 mm/s that resulted in horizontal abduction. Force that developed passively in the pectoralis major muscle was recorded with an independent uniaxial load cell. Each of the glenohumeral joints dislocated anterior-inferior, six with avulsion of the capsulolabrum from the anterior-inferior glenoid bone and eight with capsulolabral stretching. Pectoralis major muscle force as well as the joint reaction force increased with horizontal abduction until dislocation. At dislocation, the magnitude of the pectoralis major muscle force, 609.6 N +/- 65.2 N was similar to the compression force, 569.6 N +/- 37.8 N. A cadaveric model yielded an anterior dislocation with a mechanism of forcible apprehension positioning when the appropriate shoulder muscles were simulated and a passive pectoralis major muscle was included. Capsulolabral lesions resulted, similar to those observed in vivo.
... We opted for 908 of glenohumeral abduction because anteroinferior stability was the main objective for this test and this position was more reproducible in the present manual testing procedure. It was also used by Black et al. (1999) in their biomechanical study of the Bankart repair. ...
In a cadaveric instability model that leaves all muscles intact initially, we studied anteroinferior glenohumeral dislocation behavior after section of the ligaments on the humeral side of the joint. In this study, the latissimus dorsi seemed to play a role when complete section did not result in a locked anteroinferior dislocation. We therefore initiated a study to test the hypothesis that the latissimus dorsi may, in certain circumstances, depending on variations in its anatomy, influence dislocation behavior. Here, in Part I, we present the results of the anatomic study of latissimus dorsi and its tendons. The anatomy of the latissimus dorsi pertaining to the scapula and humerus was studied in 100 cadaver specimens. The distance between the uppermost part of the tendon of both the latissimus dorsi and the teres major and the edge of the articular cartilage of the humeral head (tendon-cartilage distance, TCD) as well as the width and length of the tendons were measured. Furthermore, the relationship between latissimus dorsi and the inferior angle of the scapula was studied. The tendon of the latissimus dorsi inserted at a variable distance from the cartilage of the humeral head: the TCD ranged from 12.6 to 31.6 mm (mean 21.06 mm+/-5.11 mm). The latissimus dorsi can have muscular fibers arising from the inferior angle of the scapula (type 1 scapular connection, 43%). Alternatively, there may be only a few fibrous strands between the muscle and the scapula or there may be an intervening bursa (type 2 scapular connection, 57%). This variability in the morphology of the latissimus dorsi may be a factor explaining the differences observed in a study of humerus-based sequential cutting of the glenohumeral capsule. This possibility is explored in Part II of the study. The latissimus dorsi may also complete the tendinous protection of the humeral side of the capsule generally provided by the rotator cuff.
Abstract
Background:
Arthroscopic shoulder capsulolabral repair using glenoid-based suture anchor fixation provides consistently favorable outcomes for patients with anterior glenohumeral instability. To optimize outcomes, inferior anchor position, especially at the 6-o’clock position, has been emphasized. Proponents of both the beach-chair (BC) and lateral decubitus (LD) positions advocate that this anchor location can be consistently achieved in both positions.
Hypothesis:
Patient positioning would be associated with the surgeon-reported labral tear length, total number of anchors used, number of anchors in the inferior glenoid, and placement of an anchor at the 6-o’clock position.
Study Design:
Cross-sectional study; Level of evidence, 3.
Methods:
This study was a cross-sectional analysis of a prospective multicenter cohort of patients undergoing primary arthroscopic anterior capsulolabral repair. Patient positioning in the BC versus LD position was determined by the operating surgeon and was not randomized. At the time of operative intervention, surgeon-reported labral tear length, total anchor number, anchor number in the inferior glenoid, and anchor placement at the 6-o’clock position were evaluated between BC and LD cohorts. Descriptive statistics and between-group differences (continuous: t test [normal distributions], Wilcoxon rank sum test [nonnormal distributions], and chi-square test [categorical]) were assessed.
Results:
In total, 714 patients underwent arthroscopic anterior capsulolabral repair (BC vs LD, 406 [56.9%] vs 308 [43.1%]). The surgeon-reported labral tear length was greater for patients having surgery in the LD position (BC vs LD [mean ± SD], 123.5°± 49° vs 132.3°± 44°; P = .012). The LD position was associated with more anchors placed in the inferior glenoid and more frequent placement of anchors at the 6-o’clock (BC vs LD, 22.4% vs 51.6%; P < .001). The LD position was more frequently associated with utilization of ≥4 total anchors (BC vs LD, 33.5% vs 46.1%; P < .001).
Conclusion:
Surgeons utilizing the LD position for arthroscopic capsulolabral repair in patients with anterior shoulder instability more frequently placed anchors in the inferior glenoid and at the 6-o’clock position. Additionally, surgeon-reported labral tear length was longer when utilizing the LD position. These results suggest that patient positioning may influence the total number of anchors used, the number of anchors used in the inferior glenoid, and the frequency of anchor placement at the 6 o’clock position during arthroscopic capsulolabral repair for anterior shoulder instability. How these findings affect clinical outcomes warrants further study.
Introduction
Distal biceps repair is commonly performed using various fixation devices, each having its advantages and drawbacks. All-suture soft anchor (ASSA) is a recent device mitigating some of the issues associated with previous devices.
Materials and Methods
This retrospective study including 20 patients (21 ruptures) aims to evaluate the safety and functionality of ASSA by modified tension-slide technique. All operations were performed through a single-incision anterior approach using two 2.9 mm anchors. All but 1 were men with a mean age of 50.5 years. The mean duration from injury to surgery was 14 days.
Results
At a mean follow-up of 11.8 months, compared with contralateral extremity, 18 (86%) of 21 regained full biceps strength with 5/5 flexion-supination power, while 3 displayed 4/5 power. All, except 1, returned to the previous level of function at an average of 24 weeks. As per the modified Mayo Elbow Performance Index, 18 (86%) achieved excellent and 3 (14%) had good results. Complications included lateral antebrachial cutaneous nerve palsy in 12 (resolved in 10), superficial radial nerve palsy in 1 (resolved), and heterotopic ossification in 1. No device-related complications or reruptures were noted.
Conclusion
Primary repair of distal biceps tendon ruptures through the use of the ASSA is a viable option, which in conjunction with the proposed modification of tension-slide suture fixation technique yields clinically objective and functional results.
Level of Evidence
Level IV—therapeutic.
Purpose
Suture anchors have revolutionized arthroscopic surgery, enabling direct soft tissue-to-bone repair. There are many types of anchors still used in arthroscopic shoulder operations. We sought to compare the clinical outcome of all-suture and biocomposite anchors when used in arthroscopic Bankart repair for patients suffering from anterior shoulder instability.
Methods
A single-center retrospective cohort study of 30 patients (mean age: 26.6 years, SD: 8.8 years, male/female ratio: 5/1, mean follow up: 28 months, SD: 23.8, range: 12–92) with anterior shoulder instability was conducted. Patients were divided into 2 groups based upon the type of suture anchors used for the Bankart repair: group A (14 patients) used only all-suture anchors and group B (16 patients) used only biocomposite anchors. Outcomes reported were postoperative dislocations, positive shoulder apprehension test, self-reported sense of shoulder instability, return to activities of daily living, return to sports, patient satisfaction and complications. Patient reported outcome measures (PROMs) used in this study were the Rowe Score for Instability, Constant Shoulder Score, Walch Duplay Score, The American Shoulder and Elbow Surgeons (ASES) Shoulder Score, Oxford Shoulder Instability Score and external rotation at 900 of arm abduction, external rotation at 0° of arm abduction, forward flexion, abduction, adduction and internal rotation.
Results
Rates of postoperative shoulder dislocation demonstrated no significant difference between the 2 groups (p > .05). Four postoperative dislocations happened, two in each group (14.3% and 12.5% for all suture only and biocomposite only groups, respectively), with three of them being traumatic. In addition, no significant differences were observed amongst groups regarding shoulder apprehension test (group A: 85.7%, 12/14 vs. group B: 93.8%, 15/16), sense of shoulder instability (7.1%, 1/14vs. 6.3%, 1/16), return to activities of daily living (group A: 85.7%, 12/14 vs. group B: 93.8%, 15/16), return to sports (group A: 85.7%, 12/14 vs. group B: 87.5%, 14/16), patient satisfaction (moderate level: group A 21.4%, 3/14 vs. group B 12.5%, 2/16), and PROMs.
Conclusion
The short-term failure rate and clinical/functional outcomes of arthroscopic Bankart repair using all-suture anchors is similar to the use of biocompatible anchors.
Level of evidence
Level III, retrospective cohort study.
Background:
A curved-drill guide system was recently introduced to achieve a better trajectory for a low anteroinferior anchor during arthroscopic Bankart repair. However, the clinical performance of such a device remains unclear. The purpose of this study was to evaluate the trajectory and position of the low anteroinferior suture anchor with use of the curved-guide system in clinical cases.
Methods:
We enrolled 41 cases of arthroscopic Bankart repair in this study. Of these cases, 9 were repaired using the curved drill guide whereas 32 were repaired using a conventional straight guide. Postoperative computed tomography scans were obtained, and 3-dimensional models of the scapula were reconstructed. Notable perforations of the opposite cortex by the most inferior anchors were recorded. The clock-face angle, insertion angle, and insertion distance were measured.
Results:
The anchor perforation rate in the curved-guide group (11%) was significantly lower than that in the straight-guide group (56%) (P = .02). The insertion distance in the curved-guide group was significantly shorter than that in the straight-guide group (4.0 ± 1.6 mm vs. 7.0 ± 2.4 mm, P < .01). The clock-face angle and insertion angle were significantly greater in the perforated straight-guide group than in the nonperforated groups. The percentage of anchors in the absolute safe zone (clock-face angle > 135° and < 165° and insertion angle < 100°), where no anchors perforated, was greater in the curved-guide group than the straight-guide group.
Conclusion:
Compared with the conventional straight guide, the curved-guide system provides better placement of the most inferior suture anchor during arthroscopic Bankart repair.
La inestabilidad del hombro se define como una translación glenohumeral excesiva en una o varias direcciones y que se manifiestan por episodios sintomáticos de luxaciones o de subluxaciones más o menos dolorosas. A pesar del desarrollo de las técnicas artroscópicas, la cirugía a cielo abierto de la inestabilidad del hombro conserva muchas indicaciones y sigue siendo aún la técnica de referencia debido a sus resultados validados y duraderos. Una exploración física rigurosa y unas pruebas de imagen preoperatorias completas son fundamentales para identificar las lesiones capsuloligamentarias y/o de las estructuras óseas responsables, así como para establecer la indicación quirúrgica. En la inestabilidad anterior del hombro, la vía de acceso deltopectoral es común a todas las técnicas. Se deben diferenciar dos tipos de acceso quirúrgico, una reparación «anatómica» con procedimientos capsuloligamentarios o una reparación «no anatómica» con procedimientos óseos. El tope óseo anterior aún es en la actualidad la técnica de referencia en el tratamiento de estos hombros inestables. La inestabilidad posterior del hombro es mucho menos frecuente. Las técnicas quirúrgicas requieren también procedimientos capsuloligamentarios y óseos, comparables a los de su variante anterior.
The treatment of anterior glenohumeral instability has been a topic of debate in the recent literature. Current surgical management of shoulder instability has included a variety of open and arthroscopic procedures. Open techniques for anterior reconstruction have been quite successful in preventing recurrent dislocations and continue to be the gold standard of care. In an attempt to address some of the disadvantages associated with open procedures, arthroscopic stabilization procedures have been developed. Arthroscopic capsuloligamentous repair presumably has clear advantages including better cosmesis, decreased perioperative morbidity, and a possible decrease in the loss of external rotation. Advances in arthroscopic instrumentation and improved arthroscopic techniques have increased the popularity of arthroscopic stabilization. The art of diagnosing the anatomic pathology associated with instability and proper patient selection continues to evolve. Most previous reports of arthroscopic stabilization have included small numbers of patients, variable patient pathology, and a variety of surgical techniques, making comparisons between stabilization procedures difficult. Arthroscopy can be valuable in both the confirmation of the degree and severity of the instability and to correct the pathoanatomy responsible for the instability.
The purpose of this study was to compare the results of open Bankart repair versus those of modified Bristow operation in patients with recurrent anterior dislocations of the shoulder, the last of which was caused by a minor trauma.
This study included 38 patients (34 (89.5%) male and 4 (10.5%) female) who presented recurrent dislocation of the shoulders with capsular laxity and who underwent an open Bankart repair or a modified Bristow operation. The mean age of the patients was 29.6 years (range, 17-60 years). The mean follow-up period was 5.5 years (range, 35 months to 9 years). A total of 25 patients (65.8%) underwent an open Bankart repair, whereas 13 (34.2%) underwent a modified Bristow operation. The treatment results were assessed using the Rowe score for instability.
Of the 38 shoulders assessed, 24 (63.1%) were right shoulders and 14 (36.9%) were left shoulders. Furthermore, 26 (68.4%) were the dominant shoulders of the patients, and 12 (31.6%) were the non-dominant shoulders. The mean time from the first dislocation was 3.8 years (range, 10 months to 11 years). The age at which the first shoulder dislocation occurred was 20 years or younger in 7 cases (18.4%), 21-30 years in 22 cases (57.9%), 31-40 years in 6 cases (15.8%) and 41 or older in 3 cases (7.9%). The patients had experienced 4-10 recurrent dislocations in 15 cases (39.5%), 10-20 recurrent dislocations in 10 cases (26.3%) and 20 or more recurrent dislocations in 13 cases (34.2%). The mean Rowe score was 85.6 following open Bankart repair and 81.9 following modified Bristow. No significant difference was observed between these good and excellent Rowe scores following the open Bankart repair and the modified Bristow operation (p>0.05).
Proper patient selection for the open Bankart repair and the modified Bristow operation is crucial. When the proper patients have been selected for these procedures, both produce satisfactory results for the treatment of patients with capsular laxities.
Purpose
The purpose of this study was to evaluate the accuracy of inserting a glenoid anchor at the 5:30 clockface position using a trans-subscapularis (TSS) portal versus a low anterior (LA) portal.
Methods
Five surgeons (T.D., J.C., C.V., D.J.O-H., J.S.T.) placed a single anchor in 20 fresh-frozen cadaveric shoulders. In each of 2 shoulders, surgeons used an LA portal to insert the anchor, whereas in 2 shoulders a TSS portal was used. Surgeons were directed to place the anchor at the 5:30 position at an angle 45° to the glenoid surface (axial plane) and passing perpendicular to the glenoid rim in the coronal plane. Shoulders were then dissected and computed tomographic (CT) scans obtained. Anchor position relative to the clockface was documented by 2 blinded assessors, as was the angle of insertion in the axial and coronal planes. Statistical significance was calculated with a Student t test for paired samples (confidence interval [CI], 95%; significance, P < .05).
Results
The average deviation from the 5:30 position was 48 minutes (standard deviation [SD], 31 minutes) for the LA portal (average position, 4:42 o’clock) versus 28.5 minutes (SD, 19 minutes) for the TSS group (average position, 5:02 o’clock) (P = .15). The average angle of anchor insertion in the axial plane was 67.2° (SD, 19°) for the LA portal versus 62.8° (SD, 14°) for the TSS portal (P = .49), whereas the average angle of insertion in the coronal plane was 31.3° (SD, 14°) of inferior angulation in the LA group and 14.3° (SD, 8°) of inferior angulation in the TSS group (P = .009). Of the anchors inserted, 9 of 20 (45%) showed evidence of far-cortical perforation. No difference in cortical perforation was seen between the 2 portals, with perforation more likely with anchors inserted greater than 45° in the axial plane (8 of 20) than with those inserted less than 45° (1 of 20) (P = .02).
Conclusions
The use of a TSS portal improves the angle of approach to the inferior glenoid rim in comparison with an LA portal, reducing the acuity of the angle of insertion in the coronal plane.
Clinical Relevance
The TSS portal is an option for surgeons performing arthroscopic Bankart repair using anchors low on the glenoid rim.
Bankart repair postoperative complications include loss of shoulder motion and shoulder instability. The primary reason that postoperative complications develop may be excessive imbrication of the anterior band of the inferior glenohumeral ligament (AIGHL) or inadequate repair position. The purpose of this study was to quantitatively evaluate the influence of inadequate repair by computer simulation for a normal shoulder joint.
Magnetic resonance images of 10 normal shoulder joints were acquired for 7 positions every 30° from the maximum internal rotation to the maximum external rotation with the arm abducted at 90°. The shortest 3-dimensional path of the AIGHL in each rotational orientation was calculated. We used computer simulations to anticipate the loss of motion and instability by changing the AIGHL length and insertion sites on the glenoid.
The AIGHL length measured 50 ± 5 mm at the maximum external shoulder rotation. AIGHL shortening by 3, 6, and 9 mm made the angle of maximum external rotation 80°, 68°, and 54°, respectively. A superior deviation of 3, 6, and 9 mm on the glenoid insertion resulted in a maximum external rotation angle of 85°, 79°, and 77°. An inferior deviation of 3, 6, and 9 mm produced humeral head translation of 1.7, 2.9, and 3.6 mm.
Simulation of both excessive imbrication and deviation of the insertion position led to quantitative prediction of the resulting loss of motion and instability. These findings will be useful for anticipating complications after Bankart repair.
A pesar del desarrollo de las técnicas artroscópicas, la cirugía de la inestabilidad anterior del hombro a cielo abierto sigue siendo la técnica de referencia. Una exploración clínica rigurosa y un diagnóstico de imagen apropiado son las etapas esenciales que permiten identificar las lesiones responsables y escoger entre las numerosas intervenciones propuestas. La vía de acceso deltopectoral representa el punto en común de todas estas intervenciones, que conllevan maniobras sobre las estructuras capsuloligamentosas y/o sobre el hueso. Esta vía implica disecar o seccionar el subescapular para abordar la cápsula articular. Se proponen múltiples procedimientos para minimizar las repercusiones funcionales y los riesgos de este procedimiento, y para facilitar la rehabilitación postoperatoria. Las reparaciones capsuloligamentosas anteriores y el tope anterior son intervenciones clásicas todavía muy utilizadas. Tras el análisis de los resultados, se han realizado modificaciones de estas técnicas con el objeto de mejorar la estabilidad del hombro y disminuir las complicaciones. En el caso de recidivas postoperatorias, el estado del subescapular y de las estructuras óseas condicionará los cuidados y las posibilidades terapéuticas. La rehabilitación postoperatoria debe siempre tener en cuenta las precauciones impuestas por la técnica utilizada y los objetivos fijados con el paciente antes de la intervención.
Complications during shoulder arthroscopy are very uncommon. Advanced techniques such as labral stabilization and cuff repair, however, have associated high learning curves and recognized pitfalls. Common complications are either procedure specific, such as recurrent instability or cuff tear, or unrelated to the particular procedure, including bleeding, fluid extravasation, implant problem, or iatrogenic articular injury. Most complications can be avoided through careful preoperative planning, judicious patient selection, thorough understanding of normal and variational arthroscopic anatomy, attention to surgical detail, and commitment to development of arthroscopic motor skills.
Background:
The number of anterior shoulder dislocations that predispose to recurrence is unknown; some clinicians recommend surgical repair after the initial episode and others after multiple recurrences. The purpose of this study was to quantify the forces during successive anterior dislocations of cadaveric shoulders and to inspect the capsule and labrum afterwards, in order to assess the propensity for recurrence.
Materials and methods:
Twenty-two human cadaveric shoulders were tested using a custom cadaveric shoulder dislocation device with simulated muscle loading. Each was positioned in the apprehension position and the humerus was moved in horizontal abduction until the shoulder dislocated. The joint reaction force was measured, as was the force that developed passively in the pectoralis major muscle. Following 3 successive dislocations, each was inspected for anterior capsulolabral lesions.
Results:
There was a significant decrease in force after the second dislocation. In 11, there was no labral avulsion and a significant decrease in force after the first dislocation. In the other 11, there was a labral avulsion and a significant decrease in force after the second dislocation.
Conclusion:
Two successive anterior shoulder dislocations may increase propensity for recurrence; but this is influenced by the type of capsulolabral lesion that occurs. No labral avulsion, likely a result of capsular stretching, may be a worse prognostic finding than labral avulsion after the initial episode.
The aims of this study were to evaluate the incidence of anchor penetration of the far cortex of the glenoid neck after arthroscopic Bankart repair and to compare the biomechanical properties of anchors in the 4- and 5:30- to 6-o'clock positions on the glenoid.
Twelve (6 matched pairs) fresh-frozen human cadaveric shoulders were used to simulate arthroscopic Bankart repair in the lateral decubitus position. The most inferior anchor (5:30 to 6 o'clock) and that above it (4 o'clock) were inserted via the anteroinferior portal on the glenoid using the standard technique. After both anchor insertions, anchor perforation of the glenoid far cortex was identified. Biomechanical properties were measured to determine cyclic displacement of anchors at 100 and 500 cycles, stiffness, yield load, and ultimate failure strength.
All 12 suture anchors (100%) at 5:30 to 6 o'clock penetrated throughout the far cortex, whereas only 4 anchors (33%) at 4 o'clock did so (P = .005). The mean distance the anchor tip traveled into far cortex was significantly longer at 5:30 to 6 o'clock than at 4 o'clock (6.8 ± 1.6 mm v 2.0 ± 1.6 mm, P = .001). In terms of mechanical strength, anchors at 5:30 to 6 o'clock had greater 100- and 500-cycle mean displacements than those at 4 o'clock (3.0 ± 0.5 mm v 2.5 ± 0.3 mm, P = .018 for 100 cycles; 3.5 ± 0.7 mm v 2.8 ± 0.3 mm, P = .018 for 500 cycles), although no differences in ultimate failure strength after cyclic loading were found between 2 positions (133.4 ± 40.3 and 133.7 ± 29.2 N, respectively; P = .985).
For arthroscopic Bankart repair, insertion of the most inferior anchor via the anteroinferior portal with standard technique, in the lateral decubitus position, carries a high risk of perforating the inferior far cortex of the glenoid (100% in our study). This may result in mechanical weakness of the most inferior repair specifically in the early postoperative period.
Perforation of the glenoid far cortex by the most inferior anchor and its mechanical weakness should be taken into consideration. Further study is needed to improve surgical technique to place the most inferior anchor in an optimal position by arthroscopy.
The choice of treatment for anterior instability of the shoulder via open or arthroscopic method has remained controversial after more than 10 years of experience in this arena. A review of the literature reveals an approximately 95% success rate with the open technique whereas the arthroscopic approach generally yields an approximately 85% success rate. The choice of open versus arthroscopic approach depends on many factors. In our institution, patients with: (1) Hill-Sachs lesion less than 30% of the humeral head; (2) a soft-tissue-only Bankart lesion and good capsuloligamentous structures; or (3) those who have not had more than three documented dislocation episodes are candidates for arthroscopic treatment. Others will be considered for the open treatment.
It was hypothesized that an arthroscopic Bankart repair with suture anchors supplies sufficient anterior shoulder stability, which cannot be improved by an additional capsular shift. In an experimental biomechanical human cadaver study, we tested ten fresh human cadaver shoulders in a robot-assisted shoulder simulator. External rotation and glenohumeral translation were measured at 0° and 80° of glenohumeral abduction. All measurements were performed under the following conditions: on the non-operated shoulder; following the setting of three arthroscopic portals; following an arthroscopic anterior capsular shift; following a simulated Bankart lesion; and following an arthroscopic Bankart repair. The application of three arthroscopic portals resulted in a significant increase of the anterior (P = 0.01) and antero-inferior translation (P = 0.03) at 0° and 80° abduction, as well as an increase in external rotation at 80° abduction (P = 0.03). Capsular shift reduced external rotation (P = 0.03), but did not significantly decrease translation. Simulating anterior shoulder instability, glenohumeral translation significantly increased, ranging from 50 to 279% of physiological translation. Arthroscopic shoulder stabilization resulted in a decrease of translation in all tested directions to approximately physiologic levels. External rotation in 0° abduction was thus decreased significantly (P = 0.003) to an average of 19°. The study proved that an arthroscopic anterior capsular shift in a cadaveric model decreases external rotation without a significant influence on glenohumeral translation. Arthroscopic shoulder stabilization with suture anchors thus sufficiently restores increased glenohumeral translation, but also decreases external rotation in neutral abduction. An anatomic reconstruction of the Bankart lesion without overconstraining of the antero-inferior capsule should therefore be the aim in arthroscopic anterior shoulder stabilization.
The axial distraction mobilization techniques are frequently employed for treating patients with joint hypomobility. However, there is a lack of basic biomechanical studies and description of this procedure. The purpose of this study was to analyze humeral head displacement while performing an axial distraction mobilization of the glenohumeral joint. Twelve experienced orthopedic physical therapists participated. Distraction mobilization techniques were performed in three different positions of glenohumeral abduction on a fresh cadaveric specimen. Outcome measures were displacements of the humeral head center during distraction mobilization. Result indicated that displacement of the humeral head was largest in the resting position (27.38 mm) followed by the neutral (22.01 mm) and the end range position (9.34 mm). There were significant differences for both the displacement of the humeral head (p<0.002) and the distraction forces used (p<0.015) among the three joint positions. Greater gain in mobility was obtained in distraction at the end range position. In conclusion, during distraction mobilization, the force applied by the therapist and displacement of the humeral head depends on the joint position tested. Our results also provide rationales for choosing end range distraction mobilization for improving joint mobility.
Complications associated with arthroscopic shoulder stabilization are relatively common. Excluding recurrence, complications are rarely disabling. Current statistics undoubtedly underestimate the true incidence of complications. Many complications, including neurovascular injuries and articular damage, are preventable and can be minimized through familiarity with anatomy, proper surgical technique and instrumentation, and clinical experience. Nevertheless, despite these efforts, a few complications, including recurrent instability, persist. Despite careful patient selection and attention to labral pathology and capsular laxity, arthroscopic repairs continue to have success rates lower than those achieved through open means. While cautiously proceeding toward a more complete understanding of the instability continuum, surgeons must maintain a high index of suspicion for new techniques that purport to "solve" the problem of arthroscopic shoulder stabilization, lest the history of enthusiastic but ultimately unsubstantiated claims is repeated. Outcomes must withstand the rigors of scientific scrutiny and the test of time. Without this cautious vigilance, the appeal of today's solutions becomes the fodder of tomorrow's articles about the complications of arthroscopic shoulder stabilization.
The clinical outcome of the revision surgery for the failed Bankart repair is not well known. The purpose of this study was to prospectively analyze a series of patients with recurrent instability after primary Bankart repair that were revised arthroscopically using a suture-anchor technique.
Prospective, nonrandomized outcome study.
Twenty-three patients with failed Bankart repair were treated with arthroscopic surgery and were followed up for a mean of 36 months (range, 24-52 months; SD, 9 months). There were 21 men and 2 women with the mean age of 24 years (range, 17-34 years; SD, 4.4 years). Eight patients had previously received an open Bankart repair (5 transosseous-suture technique, 3 suture-anchor technique), and 15 had received an arthroscopic repair (10 transglenoid multiple-suture technique, 5 suture-anchor technique). The revision surgery included repair of the anterior labrum using suture anchors and nonabsorbable sutures, capsular plication, and proximal shift of the inferior capsule with or without closure of the rotator interval. The characteristics of the patients, possible modes of failure, surgical findings, shoulder scores (University of California at Los Angeles [UCLA] scale, Simple Shoulder Test, and Rowe score), and clinical outcome were evaluated.
Recurrent instability developed at a mean of 21 months (range, 11-39 months; SD, 8 months) after the initial stabilization. A possible cause of failure in 5 patients was a nonanatomic repair, with the labral tissue fixed proximal or medial to the glenoid margin. At the follow-up, 15 patients had excellent results, 4 good, 3 fair, and 1 poor, according to the UCLA scale. The mean Rowe score improved from 87.3 (range, 30-100; SD, 12.6) to 91.2 (range, 40-100; SD, 14.2) (P =.023). The Simple Shoulder Test responses improved from 8 yes responses preoperatively to 11 postoperatively. Eighteen patients achieved an activity return of more than 90% of preinjury level. Five patients had recurrence after revision surgery (1 frank dislocation, 2 subluxation, 2 positive anterior apprehension sign). Engagement in contact sports was correlated with the recurrence (r =.683, P =.003). With the number available, no significant difference could be detected in the outcome between the types of the primary surgery. Arthroscopic revision Bankart repair did not result in any additional loss of external rotation compared with the contralateral side (P =.723). The most predictable factor for the functional return was preoperative range of external rotation (r =.793, P =.001).
Arthroscopic revision Bankart surgery using suture anchors can provide a satisfactory outcome, including a low recurrence rate and reliable functional return, in carefully selected patients.
Translational mobilization techniques are frequently used by physical therapists as an intervention for patients with limited ranges of motion (ROMs). However, concrete experimental support for such practice is lacking. The purpose of the study was to evaluate the effect of simulated dorsal and ventral translational mobilization (DTM and VTM) of the glenohumeral joint on abduction and rotational ROMs.
Fourteen fresh frozen shoulder specimens from 5 men and 3 women (mean age=77.3 years, SD=10.1, range=62-91) were used for this study. Each specimen underwent 5 repetitions of DTM and VTM in the plane of scapula simulated by a material testing system (MTS) in the resting position (40 of abduction in neutral rotation) and at the end range of abduction with 100 N of force. Abduction and rotation were assessed as the main outcome measures before and after each mobilization procedure performed and monitored by the MTS (abduction, 4 N m) and by a servomotor attached to the piston of the actuator of the MTS (medial and lateral rotation, 2 N m).
There were increases in abduction ROM for both DTM (mean=2.10 , SD=1.76 ) and VTM (mean=2.06 , SD=1.96 ) at the end-range position. No changes were found in the resting position following the same procedure. Small increases were also found in lateral rotation ROM after VTM in the resting position (mean=0.90 , SD=0.92 , t=3.65, P=.003) and in medial rotation ROM after DTM (mean=0.97 , SD=1.45 , t=2.51, P=.026) at the end range of abduction.
The results indicate that both DTM and VTM procedures applied at the end range of abduction improved glenohumeral abduction range of motion. Whether these changes would result in improved function could not be determined because of the use of a cadaver model.
Traumatic anterior shoulder instability is a clinical problem often observed in athletes participating in overhead activities. The standard treatment for this condition is surgical repair, which may be accomplished by an open or arthroscopic procedure. The current authors assessed the strength of open repair, by comparing glenohumeral joint forces in intact specimens with specimens with anterior dislocation and open repair. Eighteen shoulders from cadavers were tested on a custom shoulder dislocation device with simulated muscle forces. Bankart lesions were repaired using a three-suture anchor technique combined with capsular advancement. Capsular failures were addressed by sharp dissection of the labrum from bone, then repaired as above, and the experiment was repeated. One-way analysis of variance was used for analyses. All specimens dislocated anteroinferiorly, eight dislocated by bony Bankart failure, and 10 dislocated by capsular failure. Maximum joint compression force for the initial dislocation was 760 +/- 79 N for the specimens with Bankart failures and 690 +/- 59 N for the specimens with capsular failures. The maximum joint compression force for dislocation after repair measured 541 +/- 50 N for the specimens with Bankart failures and 536 +/- 46 N for the specimens with capsular failures. The forces after repair were normalized with respect to the intact shoulders. For specimens with Bankart failures, joint compression and pectoralis major forces were 72% and 62%, respectively, and 79% and 61% for specimens with capsular failures. A three-dimensional digitizing system confirmed restoration of glenohumeral position. These results support clinical data, showing that open Bankart repair adequately restores the static restraints of the glenohumeral joint that resist anteroinferior dislocation.
The treatment of anterior glenohumeral instability has been a topic of debate in the recent literature. Current surgical management of shoulder instability has included a variety of open and arthroscopic procedures. Open techniques for anterior reconstruction have been quite successful in preventing recurrent dislocations and continue to be the gold standard of care. In an attempt to address some of the disadvantages associated with open procedures, arthroscopic stabilization procedures have been developed. Arthroscopic capsuloligamentous repair presumably has clear advantages including better cosmesis, decreased perioperative morbidity, and a possible decrease in the loss of external rotation. Advances in arthroscopic instrumentation and improved arthroscopic techniques have increased the popularity of arthroscopic stabilization. The art of diagnosing the anatomic pathology associated with instability and proper patient selection continues to evolve. Most previous reports of arthroscopic stabilization have included small numbers of patients, variable patient pathology, and a variety of surgical techniques, making comparisons between stabilization procedures difficult. Arthroscopy can be valuable in both the confirmation of the degree and severity of the instability and to correct the pathoanatomy responsible for the instability.
The objective of this study was to determine the effect of progressive labral and bone loss on the articular contact area and pressures across the glenohumeral joint under compressive loads of 220 and 440 N. Eight fresh-frozen cadaver shoulders were used, and contact pressures in 4 quadrants of the glenoid were determined with a Tekscan flexible tactile force sensor. Testing conditions included intact glenoids, glenoids with the anteroinferior labrum removed, and glenoids with 3 sizes of bone defects in the anteroinferior quadrant. By means of Tekscan sensing equipment, the measured contact area over the glenolabral complex was between 49.0% and 61.5% of the calculated surface area for the intact specimens. Loss of the anteroinferior labrum decreased contact area by 7% to 15% compared with the intact specimens, and the mean contact pressure increased by 8% to 20%. With bone loss corresponding to a defect measuring 30% of the diameter in the anteroinferior quadrant, contact area across the entire glenoid decreased a mean of 41% compared with the intact specimens, whereas the mean contact pressure increased nearly 100%. When the anteroinferior quadrant of the glenoid was analyzed separately, loss of the anteroinferior labrum alone resulted in an increase in the mean contact pressure in this quadrant compared with the intact specimens (mean, 53%). Bone loss of 30% of the diameter resulted in mean contact pressures in this quadrant increasing by 300% to 400% compared with the intact specimens, with 2 of 8 specimens becoming grossly unstable. In addition, with 30% diameter bone loss, the mean contact pressure decreased by 26% in the posterosuperior quadrant, indicating a shift in loading of the cadaveric glenoid. Peak pressures followed similar trends, with labral loss alone increasing peak pressures in the anteroinferior quadrant by a mean of 28% of that seen for the intact specimens.
Joint instability is one of the most common human afflictions, affecting not only the hip, knee, and shoulder but all joints of the body. Surgical repair for joint instability is done commonly, yet has not been able to restore function consistently. Pain, recurrence of instability, joint stiffness, muscle injury, and degenerative joint disease are all too common sequelae. Because the glenohumeral joint is most commonly dislocated, efforts have been directed to understanding shoulder instability. Study has included not only the static restraints (capsulolabrum, articular surfaces, intracapsular pressure), but also their important interplay with the dynamic restraints (shoulder muscles). Furthermore, not only were muscles known to stabilize the joint studied but also may have contributed to dislocation. An in vitro, cadaveric model that included relevant shoulder muscles and a mechanism of dislocation similar to an in vivo mechanism was developed. The capsulolabral pathoanatomy that occurred after dislocation was studied. Increased understanding of joint dislocation may improve functional results after rehabilitation and surgical repair, not only at the shoulder, but also at all other joints.
The effect on joint stability of repair of type II superior labrum and biceps anchor lesions is unknown.
Increased translations of the glenohumeral joint after a simulated type II lesion will be reduced after the lesion is repaired.
Controlled laboratory study.
A robotic/universal force-moment testing system was used to simulate load-and-shift and apprehension tests on eight cadaveric shoulders to determine joint kinematics of the shoulder after venting, creation of a type II lesion, and repair of the lesion.
At 30 degrees of abduction, anterior translation of the vented joint in response to an anterior load was 18.7 +/- 8.5 mm and was significantly increased to 26.2 +/- 6.5 mm after simulation of a type II lesion. Repair did not restore anterior translation (23.9 +/- 8.6 mm) to that of the vented joint. The inferior translation that also occurred during application of an anterior load was 3.8 +/- 4.0 mm in the vented joint and increased significantly to 8.5 +/- 5.4 mm with a simulated type II lesion. After repair, the inferior translation decreased significantly to 6.7 +/- 5.3 mm.
Repair of a type II lesion only partially restored glenohumeral translations to that of the vented joint.
Surgical techniques including improved repair of passive stabilizers injured in the type II lesion should be considered.
The effects of simulated type II superior labrum anterior-posterior (SLAP) lesions were studied to determine whether the severity of the lesion affected glenohumeral joint translations. A robotic/universal force-moment sensor testing system was used to simulate load-and-shift tests by applying an anterior or posterior load of 50 N to each shoulder. The apprehension test for anterior instability was simulated by applying an anterior load of 50 N with an external rotation torque of 3 Nm at 30 degrees and 60 degrees of abduction. This loading protocol was repeated after creating two type II SLAP lesions of different severity. In the first the superior labrum and the biceps anchor were elevated subperiosteally from the glenoid bone (SLAP-II-1), and in the second the biceps anchor was completely detached (SLAP-II-2). Statistical analysis was performed with a 2-factor repeated-measures analysis of variance followed by multiple contrasts, and the significance level was set at P <.05. At 30 degrees of abduction, anterior translation of the vented joint from anterior loading was 18.5 +/- 8.5 mm. It was significantly increased (26.2 +/- 6.5 mm, P =.03), after the SLAP-II-2 lesion and compared with the SLAP-II-1 lesion (25.0 +/- 6.8 mm, P =.03). Increases in anterior translations at 60 degrees of abduction were not significantly differ in comparison to the two SLAP lesions. Inferior translation also resulted from anterior loading. At 30 degrees of abduction in the vented joint, it was 3.8 +/- 4.0 mm and was significantly increased (8.5 +/- 5.4 mm, P =.05) after the SLAP-II-2 lesion, no different than that after the SLAP-II-1 lesion (7.8 +/- 4.9 mm). No significant increases in anterior translation occurred in response to the combined loading condition between the two SLAP lesions. Glenohumeral translation was increased, regardless of severity, after simulation of type II SLAP lesions. During stabilizing surgical interventions, passive stabilizers that are injured in the type II SLAP lesion should be considered as well as dynamic activity in the tendon of the long head of the biceps brachii.
In a cadaveric instability model that leaves all muscles intact initially, the latissimus dorsi seemed to play a role when complete section of the glenohumeral capsuloligamentous structures did not result in a locked anteroinferior dislocation. The present study was carried out to determine whether the latissimus dorsi does truly affect dislocation in a modified cutting protocol, and to find an anatomic explanation for this apparent behavior. This article (Part II) details the results of a sequential cutting study and relates these results with the anatomic findings of Part I. In 75 shoulders, the influence of the latissimus dorsi on dislocation behavior in the apprehension position after section of all capsuloligamentous structures was examined. After cutting all capsuloligamentous structures, either on the glenoid or on the humeral side, the tendon of either the latissimus dorsi or the subscapularis was cut. Capsular lesions on the glenoid side (20 shoulders) resulted in a locked dislocation in 16 specimens. In the other four shoulders, there was a metastable dislocation after cutting the entire capsule, which did not change after cutting either tendon. With lesions on the humeral side (55 shoulders), three possibilities arose: metastable (17 shoulders), locked anterior (9 shoulders) or locked anteroinferior (29 shoulders) dislocation. This difference in dislocation behavior was related to the variability of the tendon-cartilage distance (TCD) and the type of scapular connection of the latissimus dorsi. A locked anteroinferior dislocation was always observed when the TCD was more than 20 mm, regardless of the type of scapular connection. With a TCD < 20 mm, a metastable dislocation was the result when there was a type 1 scapular connection and a locked anterior dislocation was seen when there was a type 2 scapular connection. The tendon of the latissimus dorsi can restrain the humeral head from dropping inferiorly or can lead to a spontaneous reduction of a dislocation, depending on its anatomy. This effect can only take place in the infrequent situation of humeral avulsion of the glenohumeral ligaments. This may be an explanation for the relative paucity of these lesions in clinical instability series.
During the past decade, developments in arthroscopic technology have made arthroscopic repair of labral lesions feasible. However, results with the use of the transglenoid suture technique, or with the use of bioabsorbable tacks, have remained variable in the literature, and the recurrence rates are still inferior to those of open Bankart repair.
Arthroscopic Bankart repair with suture anchors can re-create translational and rotational range of motion of the intact glenohumeral joint, and the number of preoperative dislocations has an influence on the result.
Controlled laboratory study.
Twelve cadaveric shoulders were tested in a robot-assisted shoulder simulator. Anterior and posterior translation and external rotation were measured for intact, dislocated (shoulders were randomly selected to 1 of 3 groups, which were dislocated 1, 3, or 7 times), and repaired conditions at 0 degrees and 90 degrees of glenohumeral elevation.
After shoulder dislocation, a significant increase was found in translation and rotation, confirming the creation of a traumatic shoulder instability model. Further testing of the specimen revealed that translational and rotational ranges of motion were reduced by arthroscopic Bankart repair at both testing positions. External rotation was decreased significantly at 0 degrees and 90 degrees of abduction. No significant differences were found between the 3 dislocation groups.
The results demonstrate a sufficient biomechanical performance of arthroscopic Bankart repair using suture anchors in a traumatic anterior shoulder instability model. With the numbers available, no relationship was found between the number of dislocations and the postoperative result concerning translational or rotational motion.
Glenohumeral translation and rotation after arthroscopic Bankart repair with use of suture anchors approached near normal values, confirming the clinical success of this technique.
Although an anteroinferior capsulolabral detachment (typical Bankart lesion) has been evaluated in other experimental studies, it has not yet been tested with an apprehension test in an intact shoulder model.
Adjacent combinations of 4 zones of the capsuloligamentous complex were sequentially detached from the glenoid neck in 50 cadaveric shoulders. Stability was tested before and after each resection step: inferior stability with a sulcus test and anterior stability with an anterior drawer test and with a load-and-shift test in the apprehension position.
A metastable anteroinferior dislocation occurred in 18 specimens after section of 3 zones and in 14 only after section of 4 zones. A locked dislocation occurred after section of all 4 zones in 33 specimens and in the other 17 shoulders only after the posterior capsule was also cut.
The humeral head cannot dislocate anteroinferiorly when there only is a Bankart lesion. In our study superior and posterior extension was necessary before the tensioning mechanism in external rotation and abduction failed enough for dislocation to occur.
Because the Bankart lesion is most likely not the only lesion present in patients with recurrent dislocation, a careful search for other lesions needs to be done when one is attempting surgical treatment. These lesions would need to be treated as well if one wants to avoid the risk of residual instability.
Arthroscopic surgery requires appropriate surgical implants for effective fixation of tendons and ligaments to bone. Biodegradable suture anchors are being used with increasing frequency for various procedures in sports medicine. As companions to these biodegradable suture anchors, new sutures have been developed which possess greater strength and different material properties from the conventional braided polyester suture. Biodegradable polymers currently found in sutures and suture anchors include poly-L-lactic acid, poly-D, L lactic acid, polydioxanone, polyglycolic acid and their copolymers. Suture anchors are now available preloaded with a choice of conventional braided polyester sutures or some version of ultrahigh molecular weight polyethylene ("super") sutures. Most new suture anchors come with 2 sutures. The manner in which these sutures are attached to the anchor varies and may consist of 2 separate eyelets or 2 slots either parallel to one another or at different angles to one another. Some anchors have a very large single eyelet that allows for 2 or more sutures.
Successful outcome of a Bankart procedure depends on knowledge of the effects of capsulolabral lesions on joint biomechanics. The joint reaction force, through "concavity compression," is integral to glenohumeral stability. In this study, we applied loads to the tendons of the rotator cuff and deltoid (anterior and middle portions) of five cadaver upper limbs. The joint reaction force was measured with a 6 degrees of freedom load cell for the intact condition and each of two test conditions: (1) incision and (2) partial resection of the anteroinferior capsulolabrum. We used analysis of variance to compare joint reaction forces resolved into that which is directed perpendicular (compression force), anterior, and superior to the glenoid. Compression force for the two different capsulolabral lesions of the glenohumeral joint was the same, 133 N +/- 13 N, a small 12% decrease compared to the intact condition (151 N +/- 13 N). This difference was not statistically significant. Results were similar for the components of the joint reaction force directed anterior and superior. Joint reaction force was not meaningfully altered after anteroinferior capsulolabral lesions were simulated. Because glenohumeral joint stability involves complex interplay of static and dynamic restraints, additional shoulder injuries may be necessary for the joint reaction force to be abnormal.
Shoulder arthroscopy continues to use minimally invasive techniques to diagnose and treat the athlete's shoulder. Instability can result from trauma or repetitive forceful movements. Arthroscopy stabilization includes multiple quadrant surgery, proper capsular tensioning, and allows dynamic evaluation of the anatomic repair without disruption of the subscapularis.
Bone deficits may limit soft tissue stabilization procedures. The arthroscope is helpful in determining the amount of glenoid bone loss, Hill-Sachs impression, positions of engagement, and associated soft tissue laxity that may compromise or alter treatment.
A series of 450 patients are presented to review repairs-including 20 first-time dislocators, 24 revision surgeries, 330 suture anchor repairs, and 120 capsular repairs. Successful stabilization occurred in 93% of the patients studied.
Successful management of the unstable athlete's shoulder includes early intervention, near-normal range of motion, absent apprehension, and normal strength and function. Anatomic repairs provide the best opportunity for the athlete to return to their sport.
This study investigated whether an anteroinferior capsulolabral lesion is sufficient to allow the humeral head to dislocate and whether a limited inferior approach for creating the lesions influenced the results compared with an all-arthroscopic approach. Four ligamentous zones of the glenohumeral capsule were sequentially detached from the glenoid neck and labrum in 20 cadaver shoulders through an inferior approach. Before and after each resection step, inferior stability was tested using a sulcus test and anterior stability using a drawer test and an apprehension maneuver. Dislocation was only possible when at least 3 zones were cut. This study confirmed that superior and posterior extension of the classic anteroinferior Perthes-Bankart lesion is necessary before the capsular restraint in external rotation and abduction is overcome and dislocation occurs. Lesions other than the Perthes-Bankart need to be investigated when recurrent dislocation is treated, because this anteroinferior injury is most probably not the sole factor responsible for the instability.
Thirty-seven of 41 consecutive patients with recurrent anterior instability of the shoulder were retrospectively observed for a mean of 5.6 years (range, 4 to 10) after an arthroscopic stabilization procedure had been per formed. The operative technique involved the use of transglenoid sutures to repair the capsule and labrum. According to the criteria established by Rowe, 27 pa tients (74%) had good or excellent results, and 3 pa tients (7%) were graded as fair. Seven patients (19%) developed recurrent instability after the procedure and had failed results. Failure rates were equal in patients with a history of recurrent dislocation and those with recurrent subluxation. Absence of a Bankart lesion at operation was associated with postoperative instability (P = 0.03). The presence or size of humeral head defects did not influence the result. Eight of 12 athletes who engaged in sports requiring repetitive overhead shoulder motion returned to full activity, and none of the 12 developed instability after operation. Four of the 13 patients who participated in contact sports or rec reational skiing developed postoperative instability (P = 0.21). All failures occurred within 2 years of the procedure.
Unlabelled:
The static restraints of the scapulohumeral joint provide stability for the humeral head in the glenoid cavity, limit extremes of motion of the glenohumeral joint, and guide positioning of the humerus during normal shoulder movement. Eleven fresh-frozen cadaver shoulders of unknown age were attached to a shoulder motion device that allowed measurement of motion in three planes with an accuracy to 0.5 degrees. Four shoulders underwent motion analysis and seven were used for strain gauge analysis of the static scapulohumeral ligamentous restraints. The results of the motion analysis demonstrated that any attempt at simple motion (flexion, extension, abduction, internal or external rotation) resulted in coupled motion in two additional planes. The strain gauge data, expressed as a percent of total tension for each ligament tested, demonstrated a reciprocal tension-sharing relationship among all ligament components and a transference of tension among these components when original and new joint positions were compared. These data provide an in vitro model of shoulder restraint function to explain primary restraint, tension sharing, and transference of tension functions in the in vivo scapulohumeral joint.
Clinical relevance:
These principles of shoulder function have application in the treatment of instability and frozen shoulder syndrome, and provide an in vitro model to better understand static restraint function in the throwing mechanism.
We have demonstrated that certain passive motions of the glenohumeral joint are reproducibly accompanied by translation of the head of the humerus on the glenoid. We investigated the relationship of these translations to the position of the glenohumeral joint and to applied torques and forces in seven isolated glenohumeral joints from fresh cadavera, using a six-degrees-of-freedom position sensor and a six-axis force and torque transducer. Reproducible and significant translation occurred in an anterior direction with glenohumeral flexion and in a posterior direction with extension. We also observed translation with cross-body movement. The translation occurring with flexion was obligate in that it could not be prevented by the application of an oppositely directed force of thirty to forty newtons. Operative tightening of the posterior portion of the capsule increased the anterior translation on flexion and cross-body movement and caused it to occur earlier in the arc of motion compared with the intact glenohumeral joint. Operative tightening of the posterior part of the capsule also resulted in significant superior translation with flexion of the glenohumeral joint.
We investigated the stabilizing mechanism of the glenohumeral joint that prevents anterior dislocation by anatomical dissections of the subscapularis, the shoulder capsule, and the superior, middle, and inferior glenohumeral ligaments in thirty-six shoulders of embalmed cadavera. We also performed roentgenographic studies of ten unembalmed cadaver shoulders in which radiopaque markers were used to demonstrate the position, tightness, and laxity of the subscapularis muscle and of the middle and inferior glenohumeral ligaments during external rotation of the shoulder at zero, 45, and 90 degrees of abduction. The subscapularis muscle and the three glenohumeral ligaments were cut in different sequences to determine their relative contributions to stability (limitation of external rotation). The conclusions from these experiments were that at zero degrees of abduction, the subscapularis muscle stabilizes the joint to a large extent; at 45 degrees of abduction, the subscapularis, middle glenohumeral ligament, and anterosuperior fibers of the inferior glenohumeral ligament provide the stability; and as the shoulder approaches 90 degrees of abduction, the inferior glenohumeral ligament prevents dislocation during external rotation.
Of 161 patients with 162 shoulders operated on during a thirty-year period (1946 to 1976), 124 were re-examined and twenty-one answered a questionnaire. The lesions found at surgery were separation of the capsule from the anterior glenoid rim in 85 per cent, a Hill-Sachs lesion of the humeral head in 77 per cent, and damage to the anterior glenoid rim (including fracture) in 73 per cent. There were five recurrences (3.5 per cent) after repair by the method described in the 145 shoulders that were followed. Only one of the forty-six patients with dislocation on the dominant side and one of the thirty-one with dislocation on the non-dominant side failed to return to the competitive athletic activities in which they participated prior to injury. The results at follow-up were rated excellent in 74 per cent, good in 23 per cent, and poor in 3 per cent. Ninety-eight per cent of the patients rated their result as excellent or good. Sixty-nine per cent of the shoulders had a full range of motion, and only 2 per cent of these shoulders redislocated. A fracture of the rim of the glenoid did not increase the risk of recurrence, while a moderate to severe Hill-Sachs lesion increased the risk only slightly. We concluded that with the meticulous technique of the Bankart repair as described, postoperative immobilization is not necessary, early return of motion and function can be expected, and resumption of athletic activities with no limitation of shoulder motion is possible for most patients.
The purpose of this study was to determine the contri butions of specific capsuloligamentous structures to restraining superior-inferior translation of the glenohu meral joint. Eleven cadaveric shoulders were tested using a four degrees-of-freedom test apparatus. The humerus was free to translate in three planes and free to flex and extend when a superior and inferior force of 50 N was applied. Testing was performed in three positions of abduction (0°, 45°, and 90°) and three positions of rotation (neutral, maximum internal, and external). Shoulders were tested intact, vented, and after division of specific capsuloligamentous structures. The primary restraint to inferior translation of the ad ducted shoulder was the superior glenohumeral liga ment. The coracohumeral ligament appeared to have no significant suspensory role. With progressive abduc tion, the anterior and posterior portions of the gleno humeral ligament become the main static stabilizers resisting inferior translation: the anterior portion was the primary capsular restraint at 45° of abduction, while the posterior portion was the primary restraint at 90° of abduction, neutral rotation.
Our results indicate that clinical assessment of glenohumeral translation in the superior-inferior plane should be performed in multiple positions of abduction and rotation.
The purpose of this study was to characterize the role of the capsule in the interval between the supraspinatus and subscapularis tendons with respect to glenohumeral motion, translation, and stability. We used a six-degrees-of-freedom position-sensor and a six-degrees-of-freedom force and torque-transducer to determine the glenohumoral rotations and translations that resulted from applied loads in eight cadaver shoulders. The range of motion of each specimen was measured with the capsule in the rotator interval in a normal state, after the capsule had been sectioned, and after it had been imbricated. Operative alteration of this capsular interval was found to affect flexion, extension, external rotation, and adduction of the humerus with respect to the scapula. Modification of this portion of the capsule also affected obligate anterior translation of the humeral head on the glenoid during flexion. Limitation of motion and obligate translation were increased by operative imbrication and diminished by sectioning of the rotator interval capsule. Passive stability of the glenohumeral joint was evaluated with the use of anterior, posterior, and inferior stress tests. Instability and occasional frank dislocation of the glenohumeral joint occurred inferiorly and posteriorly after section of the rotator interval capsule. Imbrication of this part of the capsule increased the resistance to inferior and posterior translation.
The tensile properties of the inferior glenohumeral ligament have been determined in 16 freshly frozen cadaver shoulders. The inferior glenohumeral ligament was divided into three anatomical regions: a superior band, an anterior axillary pouch, and a posterior axillary pouch. This yielded 48 bone-ligament-bone specimens, which were tested to failure in uniaxial tension. The superior band was consistently the thickest region, averaging 2.79 mm. The thickness of the inferior glenohumeral ligament decreased from antero-superiorly to postero-inferiorly. The resting length of all three anatomical regions was not statistically different. Total specimen strain to failure for all bone-ligament-bone specimens averaged 27%. Variations occurred between the three regions, with the anterior pouch specimens failing at a higher strain (34%) than those from the superior band (24%) or the posterior pouch (23%). Strain to failure for the ligament midsubstance (11%) was found to be significantly less than that for the entire specimen (27%). Thus, larger strain must occur near the insertion sites of the inferior glenohumeral ligament. Stress at failure was found to be nearly identical for the three regions of the ligament, averaging 5.5 MPa. These values are lower than those reported for other soft tissues, such as the anterior cruciate ligament and patellar tendon. The anterior pouch was found to be less stiff than the other two regions, perhaps suggesting that it is composed of more highly crimped collagen fibers. Three failure sites were seen for the inferior glenohumeral ligament: the glenoid insertion (40%), the ligament substance (35%), and the humeral insertion (25%). In addition, significant capsular stretching occurred before failure, regardless of the failure mode.
We assessed the effectiveness of a new suture anchor that has been designed to anchor sutures into a blind, straight hole drilled in bone. The strength of fixation in glenoid bone is 67 N for the No. 0 anchor and suture, and 82 N for the No. 2 device with suture. During 1988 and 1989, 32 patients underwent a modified Bankart reconstruction for recurrent anterior glenohumeral instability at two centers as part of a prospective study of this modified technique. There were no complications as a result of the technique. The four surgeons involved agreed that the suture anchor simplified the procedure. Seventeen patients have been reviewed, with more than 1 year followup. Ninety-four percent had good to excellent results according to the Bankart rating scale. There was one recurrent dislocation in a football player.
The gross and histologic anatomy of the inferior glenohumeral ligament was studied in 11 fresh frozen cadaver shoulders. Arthroscopic observations of the joint capsule through the normal range of motion re vealed that the inferior glenohumeral ligament is actually a complex of structures consisting of an anterior band, a posterior band, and an interposed axillary pouch. While these components of the inferior glenohumeral ligament complex were present in all 11 specimens, they were best demonstrated in some shoulders by placing the humeral head in internal or external rotation in varying degrees of abduction. Histologic examination of the joint capsule revealed that the anterior and posterior bands of the inferior glenohumeral ligament complex were readily identifiable as distinct structures comprised of thickened bands of well-organized colla gen bundles.
Although slight variations were noted in the attach ment sites of the anterior and posterior bands to the glenoid, the inferior glenohumeral ligament complex was observed to attach to the humeral neck in one of two distinct configurations. A collar-like attachment, in which the entire inferior glenohumeral ligament complex attaches just inferior to the articular edge of the humeral head, was observed in six specimens. In the remaining five specimens, the attachment was in the shape of a "V," with the anterior and posterior bands attaching adjacent to the articular edge of the humeral head and the axillary pouch attaching at the apex of the "V" distal to the articular edge.
The orientation and design of the inferior glenohu meral ligament complex supports the functional con cept of this single structure as an important anterior and posterior stabilizer of the shoulder joint.
Bankart capsulorraphy for recurrent shoulder instability produces predictable results. Time-consuming, technically demanding details of the procedure, however, discourage its use. A simplified technique and new instrumentation solving these limitations was used in 69 procedures, all performed by the same surgeon. Seventy-eight percent of these procedures were reviewed independently at a minimum of 2 years followup: 77% were asymptomatic, 12% had minimal symptoms, and 11% had residual problems. Instability recurred in six patients and was associated with a significant traumatic event in five. Thus, the inside-out Bankart modifications were effective.
The Bankart repair for chronic anterior shoulder instability effectively addresses the pathologic components responsible for repeated dislocation or subluxation. However, contrary to popular belief, the Bankart repair does not precisely restore the premorbid anatomy. The capsule is reattached to the boney rim of the anterioinferior glenoid deep to and lateral to the torn cartilagenous labrum, thus excluding the labrum from the joint anteriorly. This was demonstrated by cross-sectional cadaver dissections performed to illustrate this complex surgical anatomy to orthopaedic residents in training. In addition, when correlated with double-contrast computerized axial tomography, we noted five predominant patterns of anatomical lesions which by common use have been collectively termed the "Bankart lesion." These are: 1) the rare "classic" Bankart lesion in which the cartilagenous labrum and capsular origin are torn from the glenoid rim; 2) the capsule stripped from the scapular neck and the labrum detached from the glenoid rim remaining fixed to the overlying capsule; 3) the capsule stripped from the scapular neck and the labrum separated from the glenoid rim, but separately; 4) the labrum abraded away and no longer radiographically detectable; and 5) glenoid rim fracture.
Between 1976 and 1985, we repaired avulsion of the glenohumeral ligaments in sixty-three shoulders (sixty-one patients) that had traumatic anterior glenohumeral instability. We describe the indications for operation, the operative technique, and the findings at the time of operation. We located thirty-seven patients (thirty-nine shoulders) for clinical follow-up (average, 5.49 years). One patient had recurrent anterior dislocation four years postoperatively, but no patient needed reoperation. The average range of motion was 171 degrees of forward elevation and 84 degrees of external rotation in abduction. According to the criteria of Rowe et al., 97 per cent of the results were good or excellent.
The anterior portal has been the major operative portal through which hand and motorized instrumentation have been introduced into the glenohumeral joint. This portal has been limited with respect to its access to structures in the anteroinferior aspect of the joint. Anatomical and clinical studies were undertaken to evaluate the safety and effectiveness of the use of an anterior inferior, as well as an anterior superior portal. Seventy-eight unembalmed cadaver specimens and 34 operative cases were used in the studies. Only an "inside out" technique using blunt instrumentation is recommended in creating the anterior inferior portal. The margin of safety with respect to the musculocutaneous nerve is increased with adduction. The use of these two anterior portals greatly enhanced our ability to visualize and work directly on lesions of the glenohumeral ligament labral complex. These anterior portals can be safely created if guidelines are carefully followed by surgeons with considerable experience in shoulder arthroscopy.
In a cadaver study of 10 glenohumeral joint specimens, the anterior and posterior displacement of the humeral head was recorded after cutting parts of the rotator cuff and capsular structures applying a constant force to the humerus. The posterior structures were important for anterior stability in the first 40 degrees of abduction. Anterior subluxation was changed to luxation in the first half of abduction, but only after lesions to the anterior part of the rotator cuff and upper half of the anterior capsule. For posterior displacement, the posterior part of the rotator cuff was found significant from 0-90 degrees of abduction, and the posterior capsule between 40 degrees and 90 degrees of abduction. The anterior part of the rotator cuff and the upper part of the anterior capsule were essential in the first 40 degrees of abduction. Cutting the capsular structures only, we found that the entire anterior capsule resisted anterior displacement for 70-90 degrees of abduction, and the entire posterior capsule from 50-90 degrees of abduction. For posterior displacement, the entire posterior capsule was important from 60 to 90 degrees of abduction. Clinically, a large lesion to the posterior structures seems to be essential for any major anterior displacement, and posterior displacement leading to subluxation only seems possible in connection with a major anterior injury.
In 10 cadaver shoulder joints, the increments in external rotation were measured after successive cutting of the anterior stabilizing structures while a constant external torque was applied to the humerus, abducted in the scapula plane. The subscapularis muscle prevented anterior subluxation in the lower range of abduction. As abduction increased, the lower part of the capsule was the most important stabilizing structure. The findings suggest that it may be possible to perform more selective repairs in the treatment of recurrent anterior instability.
The role of atmospheric pressure in providing static stability of the shoulder was studied experimentally in 24 cadaveric shoulders. Atmospheric air was allowed to enter the joint after puncturing the capsule. Three types of experiment were performed: in the first, the capsule was punctured after sequential division of the muscles; in the second, atmospheric air was let in by percutaneous puncture of of the capsule without dividing the muscles; and in the third, air was first let into the joint by percutaneous puncture of the capsule and then the muscles of the shoulder were divided. It was found that the intact shoulder subluxated after percutaneous puncture even without division of the overlying muscles or the capsule. Our findings suggest that negative pressure and muscle tone are the main static stabilisers of the shoulder, rather than the joint capsule.
1. The pathogenesis of recurrent anterior dislocation of the shoulder has been studied at operation and by experiments on cadavers.
2. Lesions of the subscapularis muscle leading to lengthening and laxity have been demonstrated.
3. This lengthening is the prime factor in producing instability of the shoulder; capsular and bony defects are no more than subsidiary causes.
4. Good results have been obtained by a procedure based on this theory of etiology.
The authors' roentgenographic technique provides precise assessment of the glenohumeral relationship on the basis of two-plane examination. A group of 50 normal male subjects serve as the basis for determining normal values for the following angles or lines: projected and corrected cephalodiaphyseal angle, projected and corrected humeral retrotorsion, glenoid inclination, angle of attack, glenoid retroversion, dimension of glenoid, width of humeral head, and contact index. Two groups of patients suffering from recurrent anterior dislocation (RAD) are compared with the normal group. The shoulders with RAD do not differ significantly from the normal ones. Humeral retrotorsion, in particular, is identical. Significant differences are found between affected and unaffected sides in unilateral RAD. The diameter of the glenoid and the contact index are smaller on the dislocated side. Because the projected values seldom differ by more than 10 degrees from the calculated values, if the authors' roentgenographic technique is used, the figures can generally be accepted without correction.
Transient subluxation of the shoulder may cause the so-called dead-arm syndrome, which is characterized by a sudden sharp or 'paralyzing' pain when the shoulder is moved forcibly into a position of maximum external rotation in elevation or is subjected to a direct blow. This syndrome also may occur during throwing, repetitive forceful serving in tennis, or working with the arm in a strained position above shoulder level. Sixty shoulders with the dead-arm syndrome, apparently caused by transient subluxation of the shoulder, were treated and analyzed after follow-up periods ranging from two to sixteen years. Two groups of patients with this syndrome were identified. The patients in Group I had the sensation that subluxation was occurring when they used the arm in elevation; in Group II, the patients were not aware of slipping out or instability of the shoulder. Both groups had similar mechanisms of injury, similar symptoms and physical findings, comparable pathological lesions at operation, and similar results after the same surgical treatment. A Bankart procedure was performed in thirty-two shoulders in which a Bankart lesion was found, and a modified Bankart repair (capsulorrhaphy) was done in the remaining eighteen in which the labrum was intact. The results in the fifty shoulders treated surgically were 70 per cent excellent, 24 per cent good, and 6 per cent fair. Ten shoulders were treated by non-surgical means. In twenty (54 per cent) of the thirty-seven shoulders in which the superior aspect of the musculotendinous cuff was examined, a large opening in the capsule was noted in the interval between the supraspinatus and subscapularis tendons below the superior glenohumeral ligament. This opening may be a factor in anterior instability of the shoulder.
Fifty-nine patients with recurrent anterior dislocation of the shoulder underwent the Morgan arthroscopic stabilization with transglenoidal suture of the inferior glenohumeral ligament. All patients were followed-up for an average of 49 months (range, 29 to 71 months). Using Rowe's scoring system, the overall objective results were disappointing. There were 33% excellent results, 9% good, 9% fair, and 49% poor. Twenty-six patients had a further dislocation, and 3 others had recurrent subluxation on average 13 months after the operation. The failures were associated with a preoperative clinical finding of inferior hyperlaxity as demonstrated by a positive sulcus sign, a preoperative radiological finding of a bony lesion on the anterior edge of the glenoid, or an arthroscopic finding of extended ligamentous lesions at the time of operation. The results of this study are clearly worse than those reported by other investigators. Direct comparison between the reported studies is problematic and is discussed. It was concluded that arthroscopic stabilization should only be performed by interested specialists as part of controlled clinical trials.
We previously reported early results of a new technique using a suture anchor to perform a modified Bankart reconstruction. That study included patients from two medical centers and had an average followup of only 1 year. This report includes patients from a single center with followup extended to a mean of 42 months (range, 33 to 61). Between April 1988 and August 1991, 53 patients with recurrent anterior glenohumeral instability underwent modified Bankart reconstruction with the use of a suture anchor. Thirty-two patients met inclusion cri teria (identifiable Bankart lesion, open repair with suture anchors, and minimum followup of 2 years); 4 patients were lost to followup. There have been no complications as a result of this technique. Ninety-three percent of the patients in the study had objectively excellent or good results. There were 2 failures with recurrent anterior dislocation.
The use of a suture anchor can simplify the Bankart reconstruction. At average followup of 3 years, 26 pa tients have returned to presurgery activity levels without recurrent dislocation or subluxation. However, careful attention to anchor placement at the junction of articular cartilage and the glenoid neck is necessary to avoid technical failure.
A prospective study evaluating nonoperative treatment versus arthroscopic Bankart suture repair for acute, ini tial dislocation of the shoulder was undertaken in young athletes. All patients met the following criteria: 1) sus tained an acute first-time traumatic anterior dislocation, 2) no history of impingement or occult subluxation, 3) the dislocation required a manual reduction, and 4) no concomitant neurologic injury. Thirty-six athletes (average age, 20 years) met the criteria for inclusion. Group I patients were immobilized for 1 month followed by rehabilitation; they were allowed full activity at 4 months. Group II patients underwent arthroscopic Bankart repair followed by the same protocol as Group I. Group I consisted of 15 athletes. Twelve patients (80%) developed recurrent instability; 7 of the 12 have required open Bankart repair for recurrent instability. Group I consisted of 21 patients; 18 patients (86%) had no recurrent instability at last followup (average, 32 months; range, 15 to 45) (P = 0.001). One patient in Group II has required a subsequent open Bankart repair to treat symptomatic recurrence (P = 0.005).
In this study, arthroscopic Bankart repair significantly reduced the recurrence rate in young athletes who sustained an acute, initial anterior dislocation of the shoulder.
The purpose of this study was to determine the effect of sectioning of the anterior part of the inferior glenohumeral ligament (a simulated Bankart lesion) on load-induced multidirectional glenohumeral motion. Nine fresh, intact cadaveric shoulders were tested on a special apparatus that constrained three rotations but allowed simultaneous measurement of anterior-posterior, superior-inferior, and medial-lateral translation. Coupled anterior-posterior and superior-posterior translations were recorded while anterior, posterior, superior, and inferior forces of fifty newtons were applied sequentially. Testing was done in three positions of humeral elevation in the scapular plane, in three positions of humeral rotation, and with an externally applied joint-compression load of twenty-two newtons. A liquid-metal strain-gauge was placed on the posterior band of the inferior glenohumeral ligament to assess concomitant posterior capsular strain during the various test conditions. All shoulders were tested intact and again after the inferior glenohumeral ligament and the labrum had been detached from the glenoid from just superior to the anterior band of the inferior glenohumeral ligament to a point just posterior to the infraglenoid tubercle. The simulated Bankart lesion resulted in selected increases in anterior translation at all positions of elevation, in posterior translation at 90 degrees of elevation, and in inferior translation at all positions of elevation. However, these increases were very small; the maximum mean increase in translation seen over-all was only 3.4 millimeters, which occurred during inferior translation at 45 degrees of elevation.(ABSTRACT TRUNCATED AT 250 WORDS)
The authors conducted a study to determine if the long head of the biceps muscle and its attachment at the superior glenoid labrum play a role in stability of the shoulder in an overhead position. Their study used a dynamic cadaveric shoulder model that simulated the forces of the rotator cuff and long head of biceps muscles as the glenohumeral joint was abducted and externally rotated. Their data suggest that the long head of the biceps muscle contributes to anterior stability of the glenohumeral joint by increasing the shoulder's resistance to torsional forces in the vulnerable abducted and externally rotated position. The biceps muscle also helps to diminish the stress placed on the inferior glenohumeral ligament. Detachment of the superior glenoid labrum is detrimental to anterior shoulder stability as it decreases the shoulder's resistance to torsion and places a greater magnitude of strain on the inferior glenohumeral ligament.
The purpose of this paper was to report our experience with an arthroscopic technique of repair for the Bankart lesion following shoulder instability. Twenty-seven patients (average age, 21.7 years) were followed for an average of 36 months after arthroscopic suture stabilization of anterior shoulder instability. Patients were excluded if instability was multidirectional or voluntary and if there was radiographic evidence of a significant loss of glenoid bone stock. Clinical evaluation using a functional grading system showed that 10 patients were rated as excellent, 5 good, and 12 poor. Fourteen patients returned to their previous level of activity. There were 12 patients rated as failed; all had recurrent instability of the shoulder. Success was associated with a period of immobilization of 3 weeks or longer and a history of acute injury, especially subluxation. Failures were associated with shorter immobilization periods after surgery and in patients who had recurrent dislocations. The younger patient, who may not have complied with the immobilization protocol, also seemed to be associated with failure. Contact sports seems to leave a patient at high risk for recurrence. We recommend caution in the use of arthroscopic procedures for the competitive athlete in whom a second surgery and rehabilitation might mean loss of more sports participation.
The present study describes an anterior-inferior portal for arthroscopic shoulder instrumentation at the 5 o'clock position along the glenoid rim. An anterior-inferior portal was established in 14 cadaver shoulders. The portal was created in an inside-to-outside fashion, with the humerus maximally adducted, directing the guide rod as far lateral as possible. Using the described technique, a 5 o'clock portal travels through the subscapularis and lateral to the conjoined tendon. Distance between the portal and the musculocutaneous nerve was 22.9 +/- 4.9 mm (mean +/- SD), and 24.4 +/- 5.7 mm between the portal and the axillary nerve. Previously described portals were either at, or above the 3 o'clock position, resulting in an acute, difficult angle of approach to the glenoid neck. Through a combination of proper arm positioning and rod insertion technique, the 5 o'clock portal can be created safely and is of great potential utility for arthroscopic shoulder stabilization procedures.
We report the clinical outcome of arthroscopic labral reconstruction using a transglenoid suture technique in a young, active-duty military population. Forty-eight patients (49 shoulders) with varying degrees of glenohumeral instability underwent arthroscopic labral reconstruction using a transglenoid suture technique. All patients had traumatic injuries to their shoulders and all patients had magnetic resonance imaging scans demonstrating anterior labral tears. Postoperatively, the patients' shoulders were immobilized for up to 6 weeks. At a mean followup of 30 months (range, 12 to 49), 17 of the 41 patients (41%) with preoperative dislocation or subluxation had recurrent instability. Nine of these patients subsequently underwent open reconstruction procedures for recurrent instability. On the basis of the Rowe rating system, 53% had excellent or good results and 47% had fair or poor results. The overall perioperative complication rate was 14%. Suprascapular nerve palsy occurred in three cases (6%). Using the Fisher exact test, we determined that immobilization for 6 weeks postoperatively correlated with a lower recurrence rate in the patients with a history of glenohumeral dislocation (P = 0.007). The results of arthroscopic labral reconstruction using transglenoid sutures in the military patient are inferior to the reported 3% to 5% recurrence rate with open Bankart procedures, and the transglenoid pin technique jeopardizes the suprascapular nerve.
Arthroscopically assisted repair of the anterior aspect of the labrum with use of a bioabsorbable tack was performed in fifty-two consecutive patients who had chronic anterior instability of the shoulder. The average age of the patients was twenty-eight years (range, sixteen to fifty years). The etiology of the instability was a traumatic injury in forty-nine patients; twenty-six of those injuries were sustained during participation in a contact sport. Fifty shoulders had a Bankart lesion. The patients were evaluated at an average of forty-two months (range, twenty-four to sixty months) after the procedure. Forty-one (79 per cent) of the patients were asymptomatic and were able to participate in sports without restriction. The repair was considered to have failed in eleven (21 per cent) of the patients. In four of them, the failure resulted from a single traumatic reinjury during participation in a contact sport, and three of these reinjuries were treated nonoperatively. The remaining seven failures occurred atraumatically. Eight patients had an open glenoid-based capsulorrhaphy as a consequence of recurrent instability. At the reoperation, no evidence of the tack was found in any patient. In seven patients, the Bankart lesion had completely healed, and the anteroinferior aspect of the capsule was patulous. Anterior stabilization of the shoulder with a bioabsorbable tack may be indicated for patients who have anterior instability but do not need a capsulorrhaphy or capsular imbrication to reduce the joint volume.
1. Fifty cases of recurrent dislocation of the shoulder are reported, operated upon by Bankart and his colleagues from 1925 to 1954.
2. This is the first detailed survey of his patients, some of whom we were unable to trace.
3. It has been confirmed that the operation is successful, and that a full range of movement can be regained after operation, though not in every case.
4. Two cases treated unsuccessfully are described and discussed.
1. Coracoid transplantation for recurring dislocation of the shoulder is described.
2. In my experience of over thirty cases only once has true dislocation recurred after this operation. Recurrence was due to avulsion of the bone block.
3. Failure to repair the original detachment of the glenoid labrum is a frequent cause of recurrence of dislocation of the shoulder. An explanation is offered for this failure; namely that the injured labrum adheres to the deep surface of the subscapularis muscle instead of reattaching itself to bone. This reinforces Watson-Jones's advice that the original dislocation should be treated by complete immobilisation in full medial rotation for three weeks.
Arthroscopic Bankart suture repair: Technique and early results
- C D Morgan
- A B Bodenstab
Role of the inferior glenohumeral ligament complex in limiting inferior translation in the glenohumeral joint
- M K Bowen
- X H Deng
- Rif Warren
The effect of capsular venting on glenohumeral laxity
- T D Gibb
- J A Sidles
- D T Harryman
- Ii
Recurrent dislocation of the shoulder
- P B Magnuson
- J K Stack
Arthrography in acute dislocation of the shoulder [Abstract]
- B Reeves